As an example of an absorbent article to absorb exudates such as urine, menstrual blood, or the like, a disposable diaper, a sanitary napkin, etc are used. These absorbent articles include an absorbent body 1 that is obtained by forming pulp fibers into a predetermined shape.
This absorbent body 1 is shaped by a fiber depositing apparatus 10a in a manufacturing line. FIG. 1A is a side view of the fiber depositing apparatus 10a shown in a partial cross-sectional view, and FIG. 1B is a cross-sectional view taken along line B-B in FIG. 1A.
The fiber depositing apparatus 10a includes a rotating drum 20 that rotates in a circumferential direction Dc. Openings of both ends of this rotating drum 20 in a width direction (a direction perpendicular to the paper surface in FIG. 1A) are closed covering with a pair of circular walls 25, 25. Thereby, a negative pressure chamber S0 is partitioned on the inner circumferential side of the rotating drum 20. Also, molds 21 having a depressed shape are disposed of an outer circumferential face 20a of the rotating drum 20. A bottom section 21a of each mold 21 has a large number of suction holes 22, through which the bottom section 21a communicates with the negative pressure chamber S0. In addition, on the outer circumferential face 20a of the rotating drum 20, a supply duct 31 discharges mixed air 3 in which pulp fibers 2 are entrained is arranged opposite.
Thus, when the mold 21 passes through the position of the supply duct 31 with rotation of the rotating drum 20, the mixed air 3 that is discharged from the supply duct 31 is sucked into the bottom section 21a of the mold 21. In conjunction with this, the pulp fibers 2 in the mixed air 3 are deposited in the mold 21 and the absorbent body 1 is formed.
As shown in FIG. 1A, negative pressure in the negative pressure chamber S0 located on the inner circumferential side of the rotating drum 20 is generated by sucking air from the negative pressure chamber S0 with an air intake duct 41, which is connected to the circular wall 25. However, as shown in FIG. 1B, the air intake duct 41 is generally connected to only one wall 25 of a pair of the circular walls 25, 25 which is disposed in the width direction. Therefore, the suction pressure distribution in the mold 21 becomes uneven in the width direction of the rotating drum 20. This makes the deposit distribution of the absorbent body 1 in the mold 21 uneven in the width direction. In an example of FIG. 1B, deposits is thicker on the left portion to which the air intake duct 41 is connected, but deposits is thinner on the right portion which is an opposite site in the figure.
In terms of this, the Patent Literature 1 discloses that in order to prevent the suction pressure distribution from being uneven in the width direction, the suction pressure distribution in the width direction is adjusted by adjusting the extending length Ld of a suction opening 43d that is located on a pipe end of the air intake duct 41 as shown with double-dotted chained line in FIG. 1B, the suction opening 43d extending inwardly negative pressure chamber S0.
Citation List
[Patent Literature].
[PTL 1] Japanese Patent Application Laid-open Publication No. 2008-231609